Sheet metal brake



Aug. 14, 1951 R. L. BERKsoN 2,564,459

SHEET METAL BRAKE Filed July 6, 1949 2 Sheets-Sheet 1 Aug. 14, 1951 R. L. BERKsoN SHEET METAL BRAKE 2A Sheets-Sheet 2 Filed July 6, 1949 INVENToR. lcarcle'ksom- Bmw/(gam Patented Aug. 14, 1951 SHEET METAL BRAKE Richard L. Berkson, Encino, Calif., assigner to erkroy Products, Inc., Burbank, Calif., a corporation of California Application July 6, 1949, Serial No. 103,198

1 Claim.

This invention relates to a bending brake for sheet metal, and more particularly to improvements in the structure, relationships and combinations of parts of such bending brakes, so as to provide a compact ensemble having a wide range of adjustments and uses, as well as affording ease of adjustment and operation.

One of the objects of my invention is to provide a bending brake for sheet metal which embodies a movable clamping jaw for holding 'a workpiece in place during bending, and has a manually operable handle and icoacting structure for actuating the clamping jaw and for keeping it in a substantially level position while raised to a released position.

Another object of the invention is to provide a bending brake for sheet metal embodying a single and readily adjustable element for determining the angle of bend of a workpiece within a wide range of limits.

My invention has for a further object the provision of a bending brake for sheet metal which incorporates a leaf bar having a portion which is removable, when desired, to reduce the limit of distance between reverse bends. It is also within the purview of this invention to provide a bending brake for sheet metal having screw adjustments for determining the radius of the bend produced in the sheet metal workpiece.

As another object, my invention comprehends the provision of a bending brake for sheet metal which includes manually operable and readily accessible adjusting; elements for selecting the positionof a clamping jaw, so as to determine the thickness of the workpiece which will be gripped and released by manual operation of a clamping jaw actuating lever.

Other objects and advantages of the invention will be apparent lfrom the following description and the accompanying drawings in which similar characters of reference indicate similar parts throughout the several views.

Referring to the two sheets of drawings:

`Fig. 1 is a top plan view of a bending brake for sheet metal which embodies a preferred' form of my invention;

Fig. 2 is a fron-t elevational view of the bend- Ving brake shown in Fig. l;

Figs. 3 and 4 are fragmentary end elevational views of the bending brake taken from the opposite ends thereof; and

Fig. 5 is a fragmentary end sectional view drawn to a larger scale than Figs. 3 and 4 and wherein different operating positions of the parts are depicted in the solid and dot and dash lines.

Having reference to the accompanying drawings, the exemplary embodiment of my invention which is disclosed for illustrative purposes includes a base I2 which, in the disclosed structure, is'internally hollow and includes bottom and top walls I3 and I4 and a rear wall f5, so as to provide substantial height to the structure for bench mounting, when desired. The top wall has a substantially flat upper surface I6 which serves as a table for supporting workpieces. Also, the top wall I4 has a substantially ,straight forward edge Il which intersects the fiat top surface I6 to form a straight and relatively sharp corner I8. At the opposite ends of the base, end plates I9 nad 29 are secured thereto by removable fastening means, such as cap screws 22 and 23 andV have outwardly projecting anges 24 and 26 adapted to use in securing the bending brake to a suitable support.

An apron 26, which is preferably in the form of a at plate having a straight edge 21 and a hollow reinforcing rib 28 secured to and extend ing along a surface thereof adjacent the base I2,

has coaxial studs 29 and 30 secured to the op posite ends thereof and journaled in aligned bearings t2 and 33 in the end plates I9. and 29' respectively. The axis of the studs 29 and 3-0 and the bearings 32 and 33 extends substantially along the corner I8 on the base, so that the apron is hingedly supported for limited rotational' movement about that corner of the base. As depicted in Fig. 5, end reinforcing partitions, such as 34, in the base I2 have notches 35 therein to accommodate the reinforcing rib 28. In order to provide a strong end and reinforcing. structure for the apron 2E, relatively heavy blocks 3S and 3l have opposing channels 38 and 39 respectively therein, which channels receive opposite end marginal portions of the apron. The studs 2S and 30 extend into and are secured to the blocks 3B and 3l. Further to'.l

reinforce the apron for the bending of relatively heavy sheet metal, a leaf bar 4) is secured to the front face thereof adjacent the edge 21. ln order, however, that the leaf bar may be removed for the purpose of making reversed bends at a minimum distance apart, removable fasteningr means, such as screws 42, are utilized for securing the leaf bar to the face of the apron. In the normal position of the apron, as depicted in Fig. 5, the edge 21 of the apron and a side 43 of the leaf bar are in substantially coplanar relationship to the top surface I6 of the base. A bar 44 is secured to the block 35 land normally extends downwardly at one end of the apron to provide a handle by which the apron is swung upwardly during a bending operation by the application of manual force thereto.

For controlling the limit .of upward swinging movement of the apron 25, thereby to control and make possible the repetition of angular bends in sheet metal within a wide range of limits, I have provided an adjustable stop mechanism 45 which is shown in Figs. 1, 2 and 3. This stop mechanism includes an` eccentric cam 46 secured to an end of the stud 29 which projects outwardly of the end plate I9. Fastening means, such as a pin 41, is utilized to prevent relative rotation between the stud 29 and the cam 41, as well as to establish fixed relative positions of those parts. A block 4'8 is secured to the end plate I9 at a position near, but spaced from the cam 46 by means such as a locating stud Q9 and a cap screw 55. A thumb screw 52 is threaded into the block i8 at a position and in a direction such that it is aligned for the abutment of one end thereof with the eccentric surface of the cam 45. Preferably, a lock nut 53 is provided on the thumb screw 52 to secure that thumb screw in a xed position after adjustment.

The shape and normal position of the cam 46 relative to the stud 29 and the apron 25 are selected so that when the apron hangs in its normal position, as illustrated in Figs 3, 4 and 5, the low portion of the cam faces the end of the thumb screw 52. In the direction of the normal movement of the cam i6 during the upward swinging movement of the apron 25, the eccentric surface of the cam 45 gradually departs from the axis of the stud 28 through a relatively large angle (for example 135 degrees). Thus, when the thumb screw 52 is to be set for a relatively small angle of swinging movement of the apron, the end of that thumb screw is set to a position relatively close to the normal position f thumb screw is set to a position more remote y from the surface of the cam. In either instance, the abutment of the cam surface with the end of the thumb screw 52 provides a positive stop for the upward swinging movement of the apron.

As another abjustment which is utilized to determine the position of a bend in a sheet metal workpiece of predetermined size, and to facilitate repetition of the positions of such bends in additional workpieces, parallel rods 54 and 55 have their ends threaded into the rear of the base I near the upper surface l5 thereof and project rearwardly therefrom. A stop bar 55 extends across the parallel rods 5d and 55, and has openings therein which slidably receive those rods, so that the stop bar is adjustable toward and from the rear of the base to a position which is a selected distance from the corner IS at the front of the base. Locking elements 51 and 58, such as thumb screws, are threaded into the stop bar 5E for engagement with the rods 54 and 55 to secure the stop bar in an adjustable position along the rods. By preference, a support plate 55 is secured to the stop bar 55, so that its upper surface is substantially at the level of the upper surface I6 of the base, thereby to 4 provide support for the end portion of a workpiece which is abutted against the stop ibar.

A clamping jaw 63 which is utilized to hold a workpiece firmly in place against the upper surface I6 of the base includes a relatively rigid bar 62 having a forwardly projecting flange portion 63 and extends practically from end-to-end 0f the ibase above the upper surface I6 and in substantially parallel relationship to the corner I8. At the rear of the lower surface of the bar 62, a heel plate 64 is secured thereto and is substantially coextensive therewith. This heel plate, in the disclosed structure, includes a longitudinal recess extending along the forward surface thereof and which forms a channel with the lower surface of the flange 63. Forward clamping elements S6 have tongues along their rear edge which nt into the channel provided by the groove 65 when the upper surfaces of those clamping elements are disposed against the surface of the flange 63.'v The clamping elements 66, as shown in Fig. 1, are of Yvaried widths and together extend across practically the full span of the ange portion 63 in abutting relationship'. Cap screws 63 are threaded into the clamping elements and extend through the flange portion 63 to hold the clamping elements in place. One or more of the clamping elements may be re.- moved, when desired, to facilitate the bending of short pieces and pieces having previously bent ends, and the like. Some of the cap screws 68 extend through slots 59 and 10 near opposite ends of the flange portions 63, so that the positions of the clamping elements may be varied and adjusted relative to the rigid bar 62. In the disclosed structure, front surfaces 1'2 of the clamping elements form an acute angle with the lower clamping surface of those elements, so as to provide for a wide range of bends which can be formed around the bending edge 61 thereof.

At the opposite ends of the flange 63 of the clamping jaw 56, blocks 13 and 14 Vare secured thereto :by fastening means, such as cap screws 15. These blocks have coaxial studs such as .'16 projecting outwardly therefrom at opposite ends of the clamping jaw and extending into slots such as 11 in movable lifting blocks 18 and 19. The lifting blocks, in turn, have .bearings and 82 respectively, therein, which bearings fit into eccentrics 83 and 34. The eccentrics are secured to opposite end portions of a shaft 8'5 which extends through the base and is journalled in the end plates I9 and 2B. At one end of the shaft 85, a handle 66 is secured thereto and projects angularly from the shaft for effecting rotational movement of that shaft thereby to produce movements of the lifting blocks which, in turn, move the clamping jaws toward and from the upper surface i6 of the base. The eccentrics 83 and Sli at the opposite ends of the shaft are, of course, aligned, so that they produce like and corresponding movements of both lifting blocks and both ends of the clamping jaw. A stop pin 81 is secured to Yand projects outwardly from the end plate 26 in alignment with the handle 86, in order to limit the movements of the eccentrics and their respective lifting blocks.

In the disclosed structure, the slots 11 into which the studs 16 extend are elongated in a direction extending toward the axis of the shaft 35. Also, thumb screws 88 and 89 are threaded into the ends of the lifting blocks and extend into the ends of the slots in a direction correspending to that of the elongation of the slots.

These thumb screws provide an adjustment by which the clamping position of the clamping jaw may be varied in reference to the upper surface I6 of the base when the eccentrics 89 and 84 are at a position, such as that illustrated in Fig. 5, in which those eccentrics will hold the clamping jaw in a gripping position against a workpiece.

As an additional support for the clamping jaw in respect to one of the lifting blocks, which additional support is adapted to maintain the clamping jaw in a relatively level position with respect to the upper surface I0 of the base while it is raised, I have provided a pin 90 which projects outwardly from one side of the lifting block 'i9 and which is aligned for engagement with a pin 92 which projects outwardly from one end of the heel plate 64 on the clamping jaw. The pins 90 and 92 engage during upward movement of the lifting blocks to raise the rear part of the clamping jaw. On the other hand, the pin 90 which projects from the lifting block 19 is below the pin 92, so that those pins do not interfere with the clamping action which is effected through downward movement of the lifting blocks, as produced by the eccentrics 89 and 94.

A further adjustment is provided for determining the position of the clamping jaw in relation to the corner I8 of the base, so as to make allowance for various thicknesses of Workpieces being bent. For effecting this latter adjustment, posts 93 and 94 are secured to the rear surface of the base at the opposite ends thereof by fastening means such as cap screws 95. These posts extend upwardly beyond the upper surface I0 of the base and have slots 9B and 91 therein through which hand screws 98 and 99 extend in a direction such that they are threaded into opposite ends of the heel plate 64 with their opposite and manually operable end portions exposed at the rear of the base. Also, opposed channels |00 and |02 are provided on opposite sides of the slots 96 and 91, slidably to accommodate peripheral protuberances |03 and |04 on the mid-portions of the hand screws 98 and 99 respectively. Preferably, and as indicated in Fig. 5, compression springs |05 are mounted in the lower ends of the slots to exert some lifting force against the protuberances on the hand screws, thereby to avoid binding of the hand screws in their respective slots during movements of the clamping jaw. It may be observed that the hand screws 98 and 99 determine the proximity of the bending edge 61 on the clamping jaw to the corner I8 on the base, while being free to move with the clamping jaws as different workpieces are clamped and removed.

In the operation of the disclosed bending brake, a workpiece is inserted between the upper surface 6 of the base and the clamping elements 66 of the clamping jaw, so that the line of the bend is between the corner i8 of the base and the bending edge 61 at the forward ends of the clamping elements. The hand screws 98 and 99 are adjusted to provide a desired radius of bend for metal of the thickness which is being bent.

The thumb screws 88 and 89 are adjusted to effect firm clamping of the workpiece between the clamping jaw and the base without continually exerting clamping force upon the handle 86 during the bending operation. With the workpiece thus held, the apron 26 is swung upwardly as indicated in dot and dash lines 29a, in Fig. 5, by manual force applied to the handle 44. The upward swinging movement of the edge 21 of the apron bends the metal around the bending edge 61 of the clamping elements. If reversed bends are desired at a spacing closer than the combined thicknesses of the apron 29 and leaf bar 40, that leaf bar may be removed. Setting of the angle of the bend is effected by adjustment of the thumb screw 52, so that it stops movement of the apron at a desired position as it is swung upwardly.

While I have illustrated a preferred embodiment of my invention, many modifications may be made without departing from the spirit of the invention, and I do not wish to be limited to the precise details of construction set forth, but desire to avail myself of all changes within the Scope of the appended claim.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States, is:

In a bending brake for sheet metal, the combination comprising a base providing a flat top surface and a straight edge, an apron provided with axially aligned studs at opposite ends, means providing bearings supporting said studs for rotational movement at positions such that the apron is swingable substantially about a line of intersection of the at top and straight edge of the base, and stop means for determining the limit of swinging movement of the apron in one direction, said stop means including an eccentric cam secured to one of the studs, and a stop screw adjustably mounted in alignment for abutment with the eccentric cam.

RICHARD L. BERKSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 836,676 Frey Nov. A'27, 1906 1,023,049 Stander Apr. 9, 1912 1,050,274 Henderson Jan. 14, 1913 1,097,874 Philippi May 26, 1914 1,162,050 Goeller Nov. 30, 1915 1,527,547 Goeller Feb. 24, 1925 2,014,485 Themar Sept. 17, 1935 2,128,295 Goodman Aug. 30, 1938 2,474,683 Linder June 28, 1949 FOREIGN PATENTS Number Country Date 27,533 Australia June 30, 1930 212,685 Switzerland Mar. 17, 1941 

